Gas turbine engines (“GTE”) are known to include one or more stages of turbine rotors mounted on a drive shaft. Each turbine rotor includes a plurality of turbine blades extending circumferentially around the turbine rotor. The GTE ignites a mixture of air/fuel to create a flow of high-temperature compressed gas over the turbine blades, which causes the turbine blades to rotate the turbine rotor. Rotational energy from each turbine rotor is transferred to the drive shaft to power a load, for example, a generator, a compressor, or a pump.
A turbine blade typically includes a root structure and an airfoil. It is known for the airfoil and the root structure to extend from opposite sides of a turbine blade platform. The turbine rotor is known to include a slot for receiving each turbine blade. The shape of each slot may be similar in shape to the root structure of each corresponding turbine blade. When a plurality of turbine blades are assembled on the turbine rotor, a gap may be formed between and/or beneath turbine platforms of adjacent turbine blades. An ingress of high-temperature compressed gas between the gaps of adjacent turbine blade platforms may cause fatigue or failure of the turbine blades due to excessive heat and/or vibration.
Various systems for regulating the flow of compressed gas around turbine blades are known. For example, it is known to use a moveable element to bridge the gap between adjacent turbine blades. When the turbine rotor is not rotating, the position of the moveable element is dictated by the force of gravity. However, when the turbine rotor is rotating, the moveable element may be forced radially outward by centrifugal force to bridge a gap between adjacent blades. While moveable elements can regulate the flow of compressed gas, current systems may be difficult to assemble and/or require an excessive amount of space.
One example of a system including a moveable pin between rotor blades is described in U.S. Pat. No. 7,104,758 to Brock et al. (“the '758 patent”). The '758 patent discloses a rotor including a plurality of rotor blades. Each rotor blade includes a blade foot, a blade leaf, and a cover plate. A gap is defined between each cover plate when the rotor blades are assembled on the rotor. Pockets are formed on two sides of each cover plate such that adjacent rotor blades form a cavity of two opposing pockets to house a moveable pin. The '758 patent discloses that the cavity spans the gap between adjacent cover plates and may be tear-drop shaped. When the turbine is rotating, the pin will move radially outward due to centrifugal force and wedge between walls of two opposing pockets to bridge the gap and reduce vibrations.
Although the system of the '758 patent may disclose using a pin for filling a gap between cover plates of adjacent turbine blades, certain disadvantages persist. For example, the construction of the cavity in the '758 patent with the disclosed tear-drop shape may inefficiently remove more material than is necessary to house and guide the moveable pin. The inefficient removal of material to form the tear-drop-shaped cavity may adversely impact the design of the cover plate, weakening the structural integrity of the cover plate and/or requiring increased thickness of the cover plate to accommodate the removal of material.